Pushbutton switch with pivotally mounted actuator



c. F. ROBBINS Jan. 20, 1970 PUSHBUTTON SWITCH WITH PIVOTALLY MOUNTED ACTUATOR Filed Jan. 5, 1968 3 Sheets-Sheet 2 Jan. 20, 1970 Filed Jan. 5, 1968 C. F. ROBBINS 3,491,218

PUSHBUTTON SWITCH WITH PIVOTALLY MOUNTED ACTUATOR I5 Sheets-Sheet 5 United States Patent 3,491,218 PUSHBU'I'ION SWITCH WITH PIVOTALLY MOUNTED ACTUATOR Clyde F. Robbins, Milwaukee, Wis., assignor to Cutler- Hammer, Inc., Milwaukee, Wis, a corporation of Delaware Filed Jan. 5, 1968, Ser. No. 695,984 Int. Cl. H01h 21/04 US. Cl. 20068 12 Claims ABSTRACT on THE DISCLOSURE A miniature pushbutton operated switch having a twopivot W-cam and operating lever for providing positive action contact operation and a single spring for providing the combined functions of uniform contact pressure on all six contacting points of the double-pole, double-throw bridging contact switch, snap action contact operation and return of the pushbutton to normal undepressed position. By substituting a pivotal operating lever for the depressible one, the switch readily converts to a momentary type.

BACKGROUND OF THE INVENTION This invention relates to the miniature switch art and more particularly to manually operable positive action snap action switches of very small size for either alternating current or direct current service which are simple in construction and easy and economical to manufacture. While miniature switches have been known heretofore, they have had one or more of the disadvantages of being too costly, too many parts, too difiicult to make or assemble, or the like. An effective approach to devising a switch as specified above would be to provide a simple design using a minimum number of parts, to use established practices and mechanism principles to more accurately predict performance whereby to save model and testing efforts, to use minimum forces and stresses to reduce the likelihood of operational troubles, to require extreme accuracy of parts only where it is easy to obtain such accuracy and to devise parts for a minimum of handling in fabrication and assembly.

SUMMARY OF THE INVENTION This invention involves a miniature positive action snap action pushbutton operated switch construction which attains the desirable characteristics of very small size with relatively large dimensional tolerances and minimum number of parts making it easy to manufacture. This construction is attained by use of the aforementioned approach to provide simple silver butt contacts and a contacting pivot of brass-to-brass and in addition thereto essentially five parts including one spring, two metal parts and two molded parts. All of these parts can be made with minimum operations. The switch can also be assembled with minimum operations by inserting and securing the stationary contacts in the base and then stacking the remaining parts into the base and clinching the cover to the base. These few parts provide a double-pole, double-throw pushbutton switch which can alternatively be made momentary action by using a modified pivotal actuating lever instead of a depressible lever.

A general object of the invention is to provide a miniature switch which is easy and economical to manufacture.

A more specific object of the invention is to provide a miniature switch having a minimum number or combination of parts and no hard-to-obtain close tolerances.

Another specific object of the invention is to provide a miniature switch which is simple in construction and capable of construction with the use of established practices and mechanism principles to enable accurate prediction 'ice of performance thereby to reduce model and testing requirements.

Another specific object of the invention is to provide a miniature pushbutton switch of the maintained type which can be converted to momentary type with minimum modification.

Another specific object of the invention is to provide a miniature pushbutton switch of the aforementioned type incorporating both positive action and snap action operations.

Another specific object of the invention is to provide a switch structure wherein a single spring provides return action and snap action and equal contact pressures on plural-pole bridging contacts.

Other objects and advantages of the invention will hereinafter appear.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and advantages of the invention and the manner of obtaining them will best be understood by reference to the following description of preferred embodiments of miniature pushbutton operated switches with snap action taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a front elevational view of a miniature two-position snap action pushbutton operated switch constructed in accordance with the invention;

FIG. 2 is a top plan view thereof;

FIG. 3 is a cross-sectional view thereof taken along line 3-3 of FIG. 4;

FIG. 4 is a cross-sectional view thereof taken along line 44 of FIG. 2;

FIG. 5 is an exploded isometric view thereof;

FIG. 6 is an isometric view of the modified operating member providing a momentary switch;

FIG. 7 is a cross-sectional view showing such momentary switch in its normal undepressed position;

FIG. 8 is a cross-sectional view thereof showing it in its depressed position; and

FIG. 9 is a cross-sectional view thereof taken along line 9-9 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is shown a pushbutton actuated switch of the type which is adapted to be rigidly secured to a pushbutton assembly, only a portion of the push rod the latter being shown in dotted lines in FIG. 1 to indicate how it is functionally associated with the switch.

As shown therein, the switch comprises an insulating base 2 open at the top and a metal frame 4 including a cover portion 4a closing the open top of the base, a pair of straps 4b extending from opposite edges of the cover portion for clinching to the base and a pair of upwardly ofi'set brackets 40 extending from the other two edges of the cover portion for securing switch to a pushbutton mechanism. Stationary contact terminals 6, 8 and 10, hereinafter described, extend through the bottom of the base for converting the switch to an external circuit.

Cover portion 4a of the frame is provided at its center with a round aperture 4d for entry of a push rod 12, shown in dotted lines in FIG. 1, to actuate the switch mechanism within the compartment in the base.

Since the pushbutton assembly to which the switch is adapted to be attached may take various forms, it has not been shown to avoid complicating the drawings. In this connection, it will sufiice to observe that such pushbutton assembly comprises a vertically reciprocable push rod 12 for actuating the switch, the pushbutton assembly being provided with a suitable stop to limit the downward movement of the push rod to that which is necessary to operate the switch with positive, or unyielding action all the way but to prevent damaging the switch mechanism by excessive force thereon after the switch has fully operated.

As shown in FIGS. 2, 3 and 4, the switch is provided with six stationary contacts including two rows of three contacts each, and a pair of movable contacts 14, one for each row of stationary contacts. Each movable contact, which is of the rocking type, is pivotally supported on the middle contact 8 of the associated row and its opposite ends overlap contacts 6 and 10, respectively, and can be rocked from bridging engagement between contacts 8 and 6 to bridging engagement between contacts 8 and 10. As will be apparent, this provides a two-position switch of the double-pole, double-throw type.

Each center stationary contact 8 provides a pivotal support for the associated movable contact. For this purpose, each center contact 8 is a flat strip of metal such as brass or the like extending within the base above the plane of contacts 6 and 10 and provided with a short lateral extension Sa, shown in FIG. 5, which fixes the contact relative to the base. Each contact 6 and 10 has a right angle bend 6a and 10a extending toward contact 8 and lying flat on the bottom of the base. These right-angled portions may have good conductivity metal contact tips secured to their upper surfaces in a common plane a short distance below the horizontal plane of the top of the middle contact.

Each movable contact 14 is a flat strip of metal such as brass or the like provided with an inverted U-bend at the middle with a U-bend on each side thereof. The inverted U-bend rests on the center stationary contact 8 to provide a brass-to-brass pivotal support for the movable contact. The U-bends provide pivotal places for a two pivot snap action contact actuator 16. The lower surfaces of the opposite end portions of the movable contact may have secured thereto good conductively contact tips to provide low resistance connections to the stationary contacts.

As shown in FIGS. 3, 4 and 5, actuator 16 is a molded part having laterally spaced upper configurations similar to a W-cam 16a and two laterally spaced pairs of edges on its lower portion with the edges 16b and 16c of each pair spaced from one another suitably as shown in FIG. 4, to be alternately received in the respective U-bends in the movable contacts. Between the spaced W-cam surfaces at the middle of the actuator is an upwardly rounded hump 16d for receipt within the lower end of an helical compression spring 18. This hump keeps the spring from sliding out of place with the lower end of the spring being pivotally supported on the relatively narrow ridges 16e extending in opposite directions from the hump. Thus, since spring 18 pushes on the middle of the actuator, the arrangement is such that the spring provides equal pressures on the four contacts or contacting points.

While a hump 16d has been shown for exemplary purposes as a means for maintaining the lower end of the spring in pivotal registration with the narrow ridge 16a of the actuator, it will be apparent that other means could be used in place thereof. For example, the lower end of the spring could be formed with a slightly projecting cross-wire and the center ridge of the W-cam surface could be provided with a complementary groove at the center in which such cross-wire could be pivotally supported.

The upper end of spring 18 is pivoted to an operating member or operator. For this purpose, the upper end of the spring bears against a pivot member 20 in the form of a small fiat metal plate having a sheared and downwardly bowed strip at its center as most clearly shown in the isometric view of FIG. 5. The recess formed by this bowed strip pivotally accommodates a center bump 22a on an operator 22. While this pivot member 20 is not absolutely necessary and spring 18 could abut operator 22, it provides a better pivot.

Operator 22 is provided with a generally flat square upper center portion having a similar sheared and downwardly bowed strip which provides a bump 22a. The center portion of the operator is provided with a pair of upwardly formed bumps 22b, one laterally on each side of bump 22a, providing pivotal engagement points with the push rod 12 shown in FIG. 1.

Operator 22 is further provided with means for rocking actuator 16. This means comprises a pair of legs 22c alined with bumps 22b integral with and bent down from laterally opposite edges of the fiat upper portion of the operator and having reduced end portions. The other two edges of the flat upper portion of the operator are provided with means guiding the operator for vertical movement within the base. This means comprises elongated, rounded cutout portions 22d which embrace complementary vertical ridges 2a molded on the inner walls of the base. External grooves 2b are provided in the base in registration with these internal ridges for receiving straps 4b of the frame and the lower ends of these straps are clinched into recesses at the bottom of the base as shown in FIG. 4 to secure the frame to the base.

Frame 4 is shown for exemplary purposes with its brackets 40 offset upwardly so that the switch will be suitably spaced from the pushbutton assembly to which it is mounted. One of these brackets is provided with a center projection and the other is provided with a center slot as shown in FIG. 2 whereby the switch is secured to a spring clip or the like which forms part of the pushbutton assembly. It will readily be apparent that if such spring clip is provided with a pair of arms for the center projection and a single arm for the center slot, the spring clip will hold the switch brackets securely to the pushbutton assembly and prevent them from moving in any direction.

Frame 4 is also provided with four downwardly bent, short tabs or projections 4e which fit partly into two pairs of recesses 20 and 2d within the upper corners of the base (FIG. 5) to fix the frame with respect to the base and partly extend into the compartment to lower the operator in FIGS. 69 as hereinafter described. Whereas recesses 20 extend into the rear wall of the base, recesses 2d extend into the front wall and additionally into the left and right walls, respectively, for pivoting a modified actuator for momentary switch action as hereinafter described. As shown in dotted lines in FIG. 2, operator 22 in the maintained switch version fits in between and clears projections 4e.

The operation of the switch of FIGS. 1-5 will now be described following which the manner of converting it to title giomentary type of FIGS. 6-9 will be readily unders 00 Assuming that the switch is initially in the position shown in FIG. 4, stationary contact terminals 6 and 8 are connected by the movable contact. Spring 18 is compressed between actuator 16 and pivot 20. The latter in turn bears against bump 22a of the operator and the operator bears against the frame to maintain the spring compressed. Since the point at which the lower end of the spring bears against the center ridges of the W-cam is to the left of the line of action of the switch in FIG. 4, such line of action being hereinafter described, actuator 16 is biased counterclockwise. As a result, the left pivotal edge 16b as seen in FIG. 4 and the left portion of the actuator press the left end of the movable contacts against respective stationary contacts 6 and press the center of the movable contacts against respective stationary contacts 8 With equal pressures.

Now, when operator 22 is moved down by push rod 12, the operator will have a tendency to and will rotate slightly counterclockwise since the spring is slanted as shown in FIG. 4 and so being slanted applies a' bias in the upper right-hand direction on the operator. The reduced end portions of legs 220 of the operator will engage the W-cam surface at its right side as seen in FIG. 4 and will rock the W-cam clockwise with positive action. At this point, it should be noted that the hollowed out part between the pivotal edges 16b and of the actuator is slightly larger than and never touches the rounded center upper portion of the movable contact. Only the pivotal edges of the actuator touch the bottoms of the grooves at the U-bends on the movable contact.

Snap action is obtained in the following manner. For clockwise rotation of actuator 16 in FIG. 4, a center line of action extends in a straight line through the left pivotal edge 16b of the actuator and the pivot at the upper end of the spring. Now, when operator 22 rocks actuator 16 clockwise, the pivot point between the lower end of the spring and the center ridge of the W-cam at 16c moves to the right. As soon as this moving pivot point crosses to the right side of the aforesaid center line of action, the spring accelerates the actuator in the clockwise direction. This movement of the pivot point to the right of the center line of action occurs just before the right pivotal edge 16c, as seen in FIG. 4, hits the bottom of the groove in the movable contact. When this occurs, the left end of the movable contact rists abruptly from stationary contact 6. Consequently, there will be no relieving of contact pressure or so-called teasing of the contacts. Instead, full contact pressure will be maintained between the left contacts 6, 8 and 14 during the initial clockwise rocking of the actuator and until the aforesaid snap action abruptly opens the left contacts 6 and 14 and closes the right contacts 10 and 14.

In the event the left ends of movable contacts 14 had stuck or become welded to stationary contacts 6, positive action breaking of the contacts takes place. For this purpose, legs 22c engage actuator 16 and the latter i forcibly rocked clockwise until pivotal edge 16c and the right-hand portion of actuator 16 forcibly separate the left end of contact 14 from contact 6 and if necessary also forcibly close the right end of contact 14 to contact 10.

For maintaining purposes, a second center line of action comes into play. As seen in FIG. 4, the first center line of atcion is in a straight line through pivotal edge 16b and the pivot point of the upper end of the spring. As the right contacts close, a second center line of action extending in a straight line through pivotal edge 16c and the pivot point of the upper end of the spring becomes functional. During the time that the movable contact is rocking clockwise, both pivotal edges 16b and 160 engage it. During this time, the movable contact rocks on the central stationary contact 8 with a snap action to closure of the right-hand contacts. In this action, the point is reached when the second line of action comes into play. This is the point when the right-hand contacts are closed and pivotal edge 16b starts to rise up from the trough in the movable contact. From this point on, the momentum of the parts and the force of operator 22 on actuator 16 causes the pivot point at 16e to be carried to the right across the second line of action. The spring will now apply a clockwise bias on the actuator to maintain the right-hand contacts closed with the proper contact pressure at all four points.

During the aforesaid operation, the second 'line of action actually shifts slightly to assist in setting the switch to its maintained condition. Referring to FIG. 4, it will be apparent that the second line of action is actually toward the left at its upper end when the operator is depressed. That is, when the operator is depressed, the upper pivot point of the spring is substantially lower than the position it occupies when the operator is restored. Consequently, the line of action through pivotal edge 16c and the upper pivot point of the spring is toward the left at its upper end from that which it occupies in FIG. 4. This leftward shift of the second line of action during depression of the operator shortens the distance that the pivot point at 166 must travel to the right for automatic maintaining action to start. In view of this, the momentum of the parts is substantially enough to carry the pivot point at 16e across the second line of action to cause the spring to bias actuator 16 clockwise. Then as the spring restores the operator upwardly to the position shown in FIG. 4, the upper end of this second line of action shifts slightly to the right but stops short of the pivot point at 16e so that clockwise bias is maintained on the actuator to keep the contacts closed.

The following the snap action just described, the single compression spring 18 obtains the following additional results. The spring restores operator 22 to its normal position when the push rod is released, that is, it acts as a return spring for the push'button and provides outward bias to keep it there. The spring provides toggle action to keep actuator 16 biased clockwise since the pivot point between the lower end of the spring and the center ridge of the actuator is now slightly to the right of the other center line of action, that is, the straight line passing through the right pivotal ridge 16c and the pivot at the upper end of the spring. In addition, the spring provides uniform contact pressure at the four contact points, that is, between the first movable contact and the first pair of stationary contacts 8 and 10 as well as between the second movable contact and the second pair of stationary contacts 8 and 10. Moreover, the spring now provides a resilient bias on the operator 22 in the upper left-hand direction whereby it tends to rotate a small amount clockwise under initial depression by the push rod for reasons hereinbefore described.

It will be apparent that while pivot member 20 has been shown at the upper end of the spring, it might be possible to do without it and to abut the upper end of the spring directly on the operator. However, this might tend to distort the spring somewhat. Although this might not unduly interfere with proper operation, it appears more desirable to use pivot member 20.

To convert the switch from the maintained type hereinbefore described to a momentary type, all that is necessary is to substitute a modified operator 24 shown in FIG. 6. The manner in which this modified operator functions to provide momentary action is shown in FIGS. 7, 8 and 9. In these FIGS. 7-9, reference characters like those in FIGS. 1-5 have been used for like parts.

As shown in FIG. 6, momentary operator 24 is like operator 22 in having a lower bump 24a for pivot member 20, a pair of upper bumps 24b for the push rod, a pair of depending legs 240 for rocking the actuator and cutout portions 24d for guiding the operator along the internal ridges in the base. In addition, momentary operator 24 is provided with a pair of forward and lateral extensions 24e or ears on its forward corners which fit into recesses 2d in the base and hook behind the shoulders thereof in the side walls to pivotally support the forward edge of the operator in the base as as shown in FIGS. 8 and 9. These ears extend forwardly, to the left in FIG. 9, to provide clearance between cutout 2411 and the associated internal rib 2a in the base to allow pivoting of the operator. The lateral extensions of these ears 24e are, of course, necessary to pivot the operator at the upper portion of the base.

The operation of the momentary switch will now be described.

This momentary switch normally maintains the movable contacts closed with equal pressures to the center and to the right-hand stationary contacts and is operable to open these right-hand contacts momentarily and at the same time to close the movable contacts to the lefthand stationary contacts momentarily with positive action. When the pushbutton is released, the switch restores to its normal position shown in FIG. 7 under spring action.

More specifically, when the push rod 12 is depressed, operator 24 pivots on recesses Zn in the base by way of its laterally projecting ears 242. As a result, the reduced lower end portions of legs 240 of the operator engage the left side of the W-cam of actuator 16 and rock it counterclockwise with positive action. During this rocking motion, the toggle mechanism and operator 24 will snap the actuator to the end of its rocking travel in the same way as hereinbefore described in connection with FIGS. 1-5. This final position of the actuator is shown in FIG. 8. It will be seen that in this position the contacts that were previously open have closed and the other contacts that were previously closed haved opened. If the contacts stick, the positive action breaks them open.

When the pushbutton is released, the switch will restore to its normal position shown in FIG. 7. This automatic restoration will be understood by reference to FIG. 8. In this illustration, it will be noted that the lower ends of legs 240 of the operator extend down along the left side of the central ridge of the W-cam, the operator being held all together in a lower position by taps 4e of the frame. Consequently, when the spring pushes the operator upwardly, it will rotate counterclockwise around its pivot at cars 24:: and the lower ends of its legs will swing to the right in an arc. In this motion, these legs will push on the central ridge of the W-cam and rock the latter clockwise overcenter until the spring will snap it back to its-original position shown in FIG. 7. It will be apparent that whereas the actuator will shift from its right pivotal edge to its left pivotal edge when the pushbutton is pressed, it will shift back from its left pivotal edge to its right pivotal edge when the pushbutton is released.

It will be apparent from the foregoing description that the maintained switch of FIGS. 1-5 and the momentary switch of FIGS. 6-9 are alike except for the operating member. In the momentary version, operating member 24 has extensions at its corners to abut bent down tabs 4e to position the operating member lower in the housing compartment. In this way, the operating member will be low enough to operate and restore actuator 16. Operating member 24 in the momentary version also has the pivotally supporting ears. These operating members can be readily fabricated in the same die by merely using inserts to cut off the corners and ears in the maintained version so that it can he slid down in the base as shown in FIGS. 2 and 4.

While the apparatus hereinbefore described is effectively adapted to fulfill the objects stated, it is to be understood that the invention is not intended to be confined to the particular preferred embodiments of miniature pushbutton operated switches with snap action disclosed, inasmuch as they are susceptible of various modifications without unduly departing from the scope of the appended claims.

I claim:

1. A miniature pushbutton switch comprising:

a housing;

stationary contacts mounted in said housing and having external terminals for connection to an electric circuit;

a movable contact pivotally supported on one stationary contact and being tiltable into and out of engagement with at least one other stationary contact;

and a spring biased toggle system movable overcenter for imparting snap action to said movable contact comprising:

an actuator for said movable contact;

means pivotally supporting said actuator on said movable contact at two points spaced on opposite sides of said one stationary contact;

said actuator being rockable on one of its pivot points and being shiftable for rocking on its other pivot point thereby to shift the effective line of action of said toggle system;

a depressible operating lever for rocking said actuator in opposite directions;

and a compression spring pivotally supported at one end on said actuator and bearing at its other end against said operating lever to bias the latter outwardly;

and the double pivot supporting means of said actuator providing when the latter is rocked on one of its pivots that the pivot point between the actuator and the adjacent end of the spring traverses the then efiective center line of action of the toggle system before the actuator shifts to its other pivot point thereby to accelerate the actuator and provide snap action tilting of said movable contact.

2. The invention defined in claim 1, wherein said movable contact comprises:

an inverted U-shaped bend forming a downwardly open trough whereby said movable contact is pivotally supported on said one stationary contact.

3. The invention defined in claim 2, wherein said movable contact further comprises:

a U-shaped bend forming an upwardly open trough on each side of said downwardly open trough for pivotally supporting said actuator at said two points.

4. The invention defined in claim 3, wherein said actuator comprises:

two parallel pivotal edges spaced from each other a distance equal to the spacing of said upwardly open troughs for pivotally supporting said actuator in either or both of the latter as said actuator is rocked.

5. The invention defined in claim 1, wherein said actuator comprises:

an insulating member having a W-cam on its upper surface including a center ridge for pivotally supporting the lower end of said compression spring and a trough on each side of said center ridge for engagement by said operating lever.

6. The invention defined in claim 5, wherein said actuator further comprises:

means cooperating with the lower end portion of said compression spring to provide a pivotal point and to maintain registration therebetween when said actuator is rocked.

7. The invention defined in claim 1, wherein:

said compression spring provides all the operating and maintaiinng forces for the switch including bias force for snap action operation of said toggle system, pres sure between the movable and stationary contacts and bias force for restoring said operating level to its normal position.

8. The invention defined in claim 1, wherein said operating lever comprises:

an upper portion which is bodily depressible within said housing against the force of said compression spring; and

downwardly projecting mens integral with said upper portion for engaging and rocking said actuator.

9. The invention defined in claim 1, wherein said operating lever comprises:

an upper portion which pivots within said housing when depressed by way of forwardly and laterally projecting ears on said upper portion and recesses in the inner wall of said housing in which said ears are pivotally supported;

and downwardly projecting means integral with said upper portion for engaging said actuator to rock it.

10. The invention defined in claim 9, wherein said downwardly projecting means comprises:

at least one depending leg having a length long enough to engage said actuator to rock it in one direction when said operating lever is pivoted by depression thereof and to engage said actuator to rock it in the opposite direction when said operating lever is pivoted back by restoring action of said compression spring.

11. The invention defined in claim 10, wherein said actuator comprises:

an insulating member having a W-cam on its upper surface including a center ridge for pivotally supporting the lower end of said compression spring and a 9 1O trough on each side of said center ridge, one of which References Cited troughs is engaged by said depending leg to rock said UNITED STATES PATENTS actuator 1n one direction, and said center ridge being engaged by said depending leg to rock said actuator 2,076,073 4/1937 Douglas 20O68 back in the other direction by restoring action of 5 2,469,336 5/1949 Kohl 20068 said compression spring to provide a momentary 2,047,950 7/ 1936 Douglas 20068 switch. 12. The invention defined in claim 1, wherein: ROBERT SCHAEFER, Pnmary Exammer said operating lever applies a positive force through 1), SMITH, JR As ista t Ex mi said actuator to said movable contact to insure op- 10 eration of the movable contact in the event it should US. Cl. X.R.

stick. 20067 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,491,218 Dated January 20, 1970 Inventor(s) Clyde F. Robbins It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 57, after "securing", insert the line 60, "converting" should be connecting Column 5, line 19, "rists" should be rises Column 7, line 6, "haved" should be have Column 8, claim 6, line 35, "point" should be joint claim 7, line 40, "maintaiinng" should be maintaining claim 8, line 50, "mens" should be means .SKMED 1 J S EnLED (SEAL) Atteat:

L. EdwardMFletnllqIr. MIA E- W, 8. J Attesting Offim Gomissionar of m 

